Circuit breaker



Jan. 14, 1941. L. R. LUDWIG ETAL CIRCUIT BREAKER Filed Oct. 9, 1937 3Sheets-Sheet l 5 R O N E v m Jan. 14, 1941- L. R. LUDWIG ETAL CIRCUITBREAKER Filed Oct. 9, 1937 s Sheets-Sheet 2 WITNESSES: g w

Jan. 14, 1941. LUDWlG ETAL 2,228,466

0 I RCUI 'I' BREAKER Filed Oct. 9, 1937 5 Sheets-Sheet 3 Patented Jan.14, 1941 UNITED STATES PATENT OFFICE CIRCUIT BREAKER Application October9, 1937, Serial No. 168,204

23 Claims. The invention relates to circuit breakers, and

more particularly, to operating means therefor. I

In a large number of applications of circuit breakers, it is desirableto provide the, breaker with a motor-driven operating mechanism foropening, closing, or resetting the breaker, and which may be set inoperation from a remote point and which also permits manual operation ofthe breaker. A mechanism of this type is disclosed in the copendingapplication of Ture Lindstrom, Serial No. 59,387, filed January 16,1936, and assigned to the assignee of this invention, which applicationbecame Patent No. 2,192,046 on February 27, 1940. The mechanism theredisclosed'comprises, in general, a motordriven crank for oscillating aconnecting rod which is releasably connected to the operating handle ofthe breaker by a handle attachment.

The handle attachment is such that when a go handle member is inserted,it automatically effects disconnection of the breaker handle from theconnecting rod to permit manual operation of the breaker by the handlemember. A resilient link is interposed between the crank and the 2;connecting rod for permitting the necessary overthrow of the crankrelative to the breaker handle to enable the mechanism to reset thebreaker.

While the above-described mechanism is satis- 30 factory in manyrespects, it possesses certain disadvantages. The mechanism requiresextremely accurate design and adjustment of the various parts to providesatisfactory operation and is relatively expensive to manufacture. Fur-5 thermore, the arrangement does not insure against breakage of theoperating handle if too great a load is imposed thereon by themechanism. The present invention constitutes an improvement over theabove-mentioned structure 40 and obviatesthe objectionable featuresthereof.

It is an object of the present invention to provide an improved motoroperating mechanism for circuit breakers, which is simple, safe andreliable in operation and inexpensive to manu- 45 facture.

Another object of the invention is the provision of an improvedmotor-operating mechanism which, after being initially set in operation,is automatic to effect either opening, closing or 50 resetting of thebreaker, and which readily permits manual operation of the breaker whendesired.

Another object of the invention is the provision of an improvedmotor-driven oscillating mecha- 55 nism for operating a circuit breaker,embodying (Cl. 200-922) F a novel clutch means which serves to normallyconnect the breaker operating member to the mechanism for movementthereby and which permits necessary overtravel of the mechanism relativeto the breaker operating member.

Another object of the invention is the provision of an operatingmechanism as described in the preceding paragraph, in which the clutchmeans is operable to automatically release the breaker operating memberfrom the mechanism when m the load imposed on the member by themechanism exceeds a predetermined safe maximum value, and which is alsooperable by a manually operated handle to release the breaker operatingmember from the mechanism to permit manual 15 operation of the breakerby the manually operated handle.

The novel features that are considered characteristic of the inventionare set forth in particular in the appended claims. The inventionitself, however, both as to structure and operation, together withadditional objects and advantages thereof, will best be understood fromthe following detailed description of a preferred embodiment thereof,when read in connection with the accompanying drawings, in which:

Figure 1 is a side elevational view, partly in section, of a circuitbreaker embodying the motor operating mechanism of the invention;

Fig. 2 is a plan view of the circuit breaker and its motor operatingmechanism shown in Fig 1;

the emergency handle being removed from the handle attachment;

Fig. 3 is an enlarged fragmentary end view,

partly in section, of the handle attachment of the motor operatingmechanism;

Fig. 4 is a side elevational view of the handle attachment shown in Fig,3;

Fig. 5 is an end elevational view of an operat- 7 ing lever which formsa part of the handle 40 attachment shown in Figs. 3 and 4 Fig. 6 is--aside elevational view of the operating lever shown in Fig. 5:

Fig. 7 is an end elevational view of the rocking lever which forms apart of the handle attachment shown in Figs. 3 and 4;

Fig. 8 is a side elevational view of the rocking lever shown in Fig. 'I;

- FigQ Q is an end elevational view, partly in section, of the motorunit and crank driven thereby; I

Fig. 10 is a side elevational view, partly in section, of the motorunit; and Q Fig. 11 is a fragmentary end elevational view of the motorunit with the end cover removed to motor.

Referring to the drawings, the circuit breaker illustrated generally atH is o! the three-polesnap-action type of the same general constructionas the circuit breaker shown and described in Patent 1,918,232, issuedto B. P, Baker and M. W. Brainard, July 11, 1932,'and assigned to theassignee of this invention. or structure and operation of this type ofcircuit breaker are set forth completely in the aforementioned patent,only so much of the circuit breaker structure is here shown anddescribed as is considered necessary for a complete understanding of thepresent invention.

Referring to Fig. 1, the circuit breaker illustrated comprises a base l3and a cooperating cover 5, both of molded insulating material, astationary contact means H, a cooperating movable contact means i9,actuating means for the contact means indicated generally at 2 I, amanual operating handle 23 of molded insulating material, and a trippingmechanism indicated generally at 25. The section illustrated in Fig. 1is taken substantially through the center pole of the breaker in orderto illustrate the common actuating means for the contacts of thebreaker. The center movable contact I! is carried by a switch arm 21which is pivoted to a U-shaped frame 29 by means of a pivot pin 3|. Theswitch arms and movable contacts carried thereby for the other two polesof the breaker are secured for simultaneous movement with the centralswitch arm 21 by means of an insulating tie bar 33, which extends acrossall three poles of the circuit breaker.

The common actuating mechanism 2| which is disposed in the center polespace of the breaker comprises a pair of toggle links 35 and 31, areleasable support 39 for the upper end of the toggle and over-centerspring means 4|, which connect the knee of the toggle with the upper endof a U-shaped operating member 43. The lower toggle link 35 is pivotedat its lower end to the switch arm 21 while the upper toggle link ispivotally connected at its upper end to the releasable support 39.

The releasable support 39 is pivoted on the main frame by means of apivot pin 45. The right-hand end of the releasable Support 39 isnormally held in latched position by means of a latching member 41 ofthe tripping means 25 to maintain the toggle in operative position. TheU-shaped operating member 43 is pivotally mounted at its lower end tothe sides 01' the main frame 28 and has the operating handle 23 securedto its upper end. A knob portion of the operating handle 23 projectsthrough an opening 49 provided therefor in the cover IS. The trippingmechanism 25 may be of the type more fully described in Patent2,047,739, issued to H. J. Lingal, July 14, 1936, and assigned to theassignee of this invention.

The operation of the circuit breaker as thus far described is briefly asfollows. To open the contact means of the circuit breaker the operatinghandle 23 is moved in a clockwise direction. The clockwise movement ofthe operating handle 23 moves the line of action 01' the overcentersprings 4| to the right, and as the line of action of the springscrosses the pivotal connection between the upper toggle link 31 and thereleasable support 39, the force exerted by the springs 4| causes thetoggle links to collapse and Since the details.

thereby move the switch arm 21 to the open circuit poution with a snapaction.

To close the breaker, the operating handle is moved in acounter-clockwise direction, and substantially the reverse action takesplace. The movement of the operating handle 23 in a counter-clockwisedirection moves the line oi action of the over-center springs 4|, andwhen their line of action crosses the pivotal connection of the link 31with the releasable support 55, the force exerted by the springs causesthe toggle links to be moved to their overset position, as shown in Fig.1, thereby moving the switch arm 21 to the closed circuit position witha snap action.

When an' overload occurs in the circuit of any one of the poles of thebreaker, the tripping mechanism 25 causes the latching member 41 torelease the right-hand end of the pivoted support 35, thus allowing thesupport 39 to be moved upwardly under the influence of the overcentersprings 4|. This'upward movement of the releasable suppo t elIectscollapse of the toggle links 35 and 31 and movement of the switch arm 21to the open circuit position.

Before the breaker can be reclosed following a tripping operation, it isnecessary to reset the actuating mechanism. In order to reset theactuating mechanism the operating member 43 is provided with a dependingprojection 5| for engaging the releasable support 39, To reset thebreaker, the operating handle 23 is moved in a clockwise direction tocause the projection 5| to engage and move the releasable support 39 toits latched position shown in Fig. 1. The operating handle is movedslightly beyond the normal open position in order to effect resetting ofthe releasable support 39, in engagement with the latching member 41.

The motor operating mechanism for the circuit breaker is indicatedgenerally at 53 and comprises in general a motor unit 55 for driving arotatable crank arm 51, and a handle attachment 58 mounted on thebreaker operating handle 23, and having a part connected to the crankarm 51 for oscillation thereby. The handle attachment 58 includes aclutch means for releasably connecting the breaker handle 23 with themotor-driven part of the handle attachment, as will be describedhereinafter.

The motor operating mechanism 53 is secured to a frame 6| by means of aplurality of bolts 52 (Fig, 2), the frame 6|, in turn, being secured tothe breaker base I! by means of a plurality of bolts 65. The frame 5| isgenerally rectangular in shape and includes a pair of angular brackets51 for mounting on the bolts which pass through the breaker base I3, thecover I5, and through suitable openings provided therefor in thebrackets 51.

The motor unit 55 comprises'a suitable casing 65 (Figs. 9. and 10)within which is mounted a driving motor 1| of the universal type. A gearcasing 13 is secured to one end of the casing 59 and an extension of thearmature shaft of the motor 1| projects into the gear casing 13. Uponthis extension is mounted a worm 15 which engages a worm gear 11. Theworm gear 11 is secured for rotation with a counter-shaft 19 rotatablymounted in suitable bearings within the gear housing 13. One end of thecounter-shaft 15 extends through a side of the gear casing 13 and hasrigidly mounted thereon a crank arm 51. The end of the crank arm 51 isprovided with a suitable crank roller 53 which is adapted to engage aslot provided therefor in a rocking lever which forms a part of thehandle attachment 53. The worm and the worm gear 11 provide a simple andinexpensive reduction gear between the crank arm 51 and the motor 1I, sothat the crank arm is driven at a considerably reduced speed compared tothe speed of the motor 1|.

The handle attachment 50 serves to connect the crank arm 51 with thebreaker operating handle 23, and comprises, in general, an operatinglever 05, a rocking lever 91, and a clutch means indicated generally at39 for releasably connecting the operating lever 35 to the rocking lever31 for movement thereby. The operating lever 05 (Figs. 5 and 6) consistsof an integral casting and is provided at its lower end with a yoke 9|for attaching the operating lever to the breaker operating handle 23.The yoke 9| has a pair of spaced lugs 93 shaped and spaced apart so asto snugly engage the knob portion of the breaker operating handle 23.The lugs 93 are provided with aligned threaded openings for receiving apair of fastening screws 95 which are adapted to pass through suitableopenings provided therefor in the breaker operating handle 23. Thescrews 95 serve to securely fasten the yoke 9| of the operating lever 95to the breaker operating handle 23.

A pair of bearing brackets 91 are secured to the opposite sides of theyoke portion 9| of the operating lever 85, the brackets 91 being securedto the opposite ends of the lugs 93 of the yoke 9I by means of fasteningscrews 99. The bearing brackets 91 serve to pivotally support therocking lever 91. Adjacent its mid-portion the lever 85 is provided withan integral bracket projection IOI. A portion I03 of the bracket IOIextends opposite and parallel to the body portion of the lever 85. Thecentral portion of the lever 05 adjacent the bracket IN and the parallelportion I03 of the bracket IOI are provided with vertical guide slotsI05 which serve to slidably support and guide a roller which forms partof the clutch means to be hereinafter described. The upper end of thelever 85 has a horizontal portion I 01 extending at right angles theretoand this portion is provided with a circular opening I 09 for a purposeto be hereinafter described.

The rocking lever 81 (Figs. '7 and 8) consists of an integral castingprovided with a vertical slot III for receiving the crank roller 03carried by the crank arm 51. The lower end of the rocklng lever 91 isprovided with a pair of spaced bearing legs II3 adapted to fit withinthe bifurcated portions of the bearing brackets 91 as best shown in Fig.3. The bearing legs II3 of the rocking lever 81 are secured for pivotalmovement in the bearing brackets 91 by means of pivot pins II5 whichengage openings H1 and H9 provided therefor in the bearing legs H3 andthe bearing brackets 91. The lever 81 is also provided with a horizontalshelf portion I2I which is off-set from the body portion of the lever.Theshelf portion I2I has an arcuate recess I23 formed therein which isadapted to receive the clutch roller I25 carried by the operating lever95. The rocking lever 91 is adapted to be oscillated by the rotation ofthe crank arm 51 when the motor H is rotated, and the operating lever 95is normally connected for movement with the rocking lever 01 by means ofa releasable clutch device.

The clutch device (Figs. 3 and 4) for releasably coupling the operatinglever 05 to the rocking lever. 81 comprises a spring pressedroller I25carried by the operating lever 05, for engaging the arcuate rollerreceiving recess I23 formed in the shelf portion I2I of the rockinglever 91, The roller I25 is rotatably carried by a roller shaft I21 theends of which are in slidable en- Bagement with the vertical guide slotsI05 of the operating lever 95.

A cylindrical roller carrying member I29 has its upper end slidablyreceived in the circular opening I09 of the portion I01 of the lever 35.The lower end of the roller carrying member I29 has a bifurcated memberI3I secured thereto. The legs of the bifurcated member I3I are providedwith a pair of aligned openings I33 for engaging the roller shaft I21 onopposite sides of the roller I25. The roller I25 is biased in a downwarddirection by means of a compression spring I35 which encircles theroller carrying member I29. The upper end of the spring I35 engages theportion I01 of the lever 95 while the lower end of the spring engagesthe bifurcated member I3I. The spring I35 serves to normally maintainthe roller I25 firmly seated in the roller receiving arcuate recess I23of the rocking lever The roller carrying member I29 is provided with avertical threaded opening I31 for receiving the lower end of anemergency operating handle I39. The emergency operating handle I39 isprovided with a reduced portion IlI forming an annular shoulder 3 whichengages the upper surface of the portion I01 of the lever 05. Theemergency handle I39 is also provided with an annular recess 5 betweenthe reduced portion IlI thereof and the annular shoulder I l3.

The annular recess 5 permits upward movement of the roller carryingmember I29, being of suflicient width to receive the upper end of thesaid roller carrying member. The threads of the reduced portion IlIengage the internal threads of the roller carrying member I29, so thatwhen the emergency operating handle I39 is turned in a clockwisedirection the roller carrying member I29 is moved upwardly to withdrawthe roller I25 from the arcuate recess I23 of the rocking lever 31. Thiseffects release of the operating lever 85 from its connection with therocking lever 01 so as to permit manual operation of the breaker bymeans of the emergency handle I39. The edges of the arcuate rollerreceiving recess I23 are rounded as indicated at I" (Fig. 8) andterminate in the sloping sides 9 of the horizontal shelf I2I. Therounded edges 1 permit the roller I25 to roll out of the recess undercertain conditions, and the sloping sides 9 permit the roller to rollback into the recess to reset the clutch mechanism following itsrelease.

The'motor II is provided with a suitable control circuit for energizingthe same to effect opening, closing or resetting of the breaker. Oneform of control circuit for the motor is disclosed in the aforementionedcopending application of Ture A. Lindstrom, Serial N 0. 59,387. Thecontrol circuit of the motor includes suitable opening and closingswitches for controlling opening or closing of the breaker, and asuitable limit switch operable to open the motor circuit immediatelyafter the contacts of the breaker have been operated which occurs beforethe breaker handle reaches either end position due to the overcenterspring mechanism 2I of the breaker. The limit switch may be of the typedisclosed in the aforementioned Lindstrom application and disposedwithin the gear casing 13 and the cover ISI for the gear casing.

In order to assist in bringing the motor to rest promptly at the end oithe stroke of the rocking lever 81, the motor is provided with asuitable brake mechanism, indicated generally at I53. The brakemechanism may be of a type similar to the brake mechanism disclosed inthe aforementioned Lindstrom application, Serial No. 59,387. The brakemechanism comprises a brake shoe carrying arm I55 secured on the end ofthe motor shaft, which carries a pair of brake shoes I51 at its oppositeends. The brake shoes I51 are pivotally mounted on the ends of the armI55 by means of pivot pins I55 and are biased by suitable spring means,not shown, in a clockwise direction about their pivot axes. The brakeshoes I51 are adapted'to engage an internal braking surface Iii formedintegral with the motor casing 55 when the motor speed increases duringoperation of the breaker actuating mechanism.

The operation of the motor operating mechanism for the breaker isbriefly as follows. To open the circuit breaker the opening controlswitch of the motor control circuit is operated so to energize themotor. The rotation of the motor effects rotation of the crank arm 51through 180 degrees at a reduced speed to cause clockwise movement ofthe rocking lever 31, as viewed in Fig. 1. Since the operating lever 35is coupled to the rocking lever 31 by means of the roller I25 engagingin the arcuate recess I23, the operating lever 85 is also rotated in aclockwise direction with the rocking lever 81. The clockwise movement ofthe rocking lever 31 and the operating lever 85 moves the breakeroperating handle I23 in a clockwise direction to eifect opening of thecircuit breaker in the manner previously described.

As soon as the overcenter springs ll of the breaker actuating mechanism2| have been moved overcenter to actuate the contacts of the breaker,the force required to complete opening movement of the breaker operatinghandle 23 becomes substantially decreased so that the driving motor 1|tends to speed up. The increased speed of the motor causes the brakeshoes I51 to be moved outwardly by centrifugal force causing the brakemechanism I53 to retard rotation of the motor shaft. At substantiallythe same time, the limit switch of the motor is open, deenergizing themotor circuit. The brake mechanism I53 acts to retard the speed of themotor shaft so that the rocking lever 31 is brought to restsubstantially at the completion of its stroke.

In closing the breaker, substantially the reverse action takes place.The closing control switch of the motor circuit is operated to energizethe motor to cause it to rotate in the same direction. The rotation ofthe motor causes the crank arm 51 to be rotated through 180 degrees toeh'ect counter-clockwise rotation of the rocking lever 81 and since theoperating lever 35 is coupled to the rocking lever by means of thespring pressed roller engaging the arcuate recess I23, the operatinglever 35 is also rotated in a counter-clockwise direction. The operatinglever 85 being connected to the breaker handle 23, moves that handlefrom the open position to the closed position to effect closing of thebreaker contacts in the manner previously described. As soon as theovercenter springs of the breaker actuating mechanism 2| have been movedover center to actuate the contacts of the breaker, the motor speeds upand eifects operation of the closed position shown in Fig. 1, to holdthe breaker operating handle 23 also in closed position. Since thebreaker is of the trip-free type, the contacts are opened, in responseto the overload irrespective of the position of the breaker operatinghandle. To reset the breaker, the opening 3 control switch of the motorcircuit is operated to eii'ect energizing of the motor 1| and movementof the rocking lever 31 and the connected operating lever 35 to thereset position. The rocking lever 31 has a slightly greater stroke thanthe normal operating stroke of the breaker operating handle 23, in orderto move the breaker operating handle 23 slightly beyond the normal openposition to its rsetting position to eil'ect resetting of the breakeractuating mechanism following the tripp ng operation.

The rocking lever 31 has a slightly greater Stroke than the stroke ofthe operating handle 23 of the breaker. The overtravel of the rockinglever 31 relative to the operating lever 35 is permitted by reason ofthe specific clutch device including the roller I25 and the arcuaterecess I23. During overtravel of the rocking lever 31 in eitherdirection, the roller I25 rolls up either side of the arcuate recess I23against the bias of the spring I35. This action of the roller duringovertravel acts to effect stopping of the motor, whose speed has alreadybeen retarded by the brake mechanism, at the ends of the stroke of therocking lever.

The clutch device comprising the roller I25 and the arcuate recess I23of the rocking lever 31 positively prevents breakage of the operatinghandle 23 of the breaker. The slope of the sides of the arcuate recess23 and the force exerted by the biasing spring I35 are such as to permitthe roller I25 to roll out of the arcuate recess to effect release ofthe operating lever 85 from the rocking lever 31 whenever the loadimposed on the breaker oprating handle 23 by the motor mechanism exceedsa predetermined maximum safe value. The force exerted by the spring I 35normally maintains the roller I25 in engagement in the recess I23 toconnect the lever 35 to rocking lever 31 for movement thereby. Thus, theclutch device normally couples the breaker operating handle 23 to theoperation thereby and also operates automatically to release the breakerhandle 23 from connection with the motor mechanism whenever the loadimposed on the breaker handle 23 exceeds a predetermined safe value.

In certain instances, it may be desirable to manually operate thecircuit breaker. To manually operate the circuit breaker, the emergencyoperating handle I33 is turned in a clockwise direction. The clockwiseturning of the emergency handle I39 moves the roller I25 upwardly todisengage it from the recess I23 of the rocking lever 31. This eflectsrelease of the operating lever 35 from its connection with the rockinglever 31. Under these conditions, the breaker may be manually operatedby means or the emergency handle I33 in the manner previously motormechanism iordescribed in connection with the manual operation of thebreaker.

The sloping sides I49 of the shelf portion I2I of the rocking lever andthe rounded ends I" of the roller receiving recess I28'permit the rollerI to roll back into its normal position in the recess I23 to reestablishthe connection between the levers 85 and 81 following either theautomatic or manual release of the clutch mechanism. To reset the clutchmechanism 88 the motor circuit is energized and the lever 81 is moved.The inclined sides I88 of the lever 81 first push the'roller I25 andthelever 85 until the lever 85 reaches one of its limits of movement.Continued movement of the rocking lever 81 then causes the roller I25 tomove upwardly along the incline I48 against its spring bias until itrolls over the rounded edge 1. The roller I25 is then seated in therecess I 23 by the bias of the spring I35.

The motor mechanism has been illustrated and described in connectionwith a particular type of circuit breaker structure; it will be readilyunderstood however that the motor mechanism is also capable of usewithvarious other types of circuit breakers and switches and also with otherforms of control devices.

While the invention has been disclosed in accordance with the provisionsof the patent statutes, it is to be understood that various changes inthe structural details thereof may be made without departing from thespirit of the invention. It is desired, therefore, that the-language ofthe appended claims be given the mined safe value and resettable afterautomatic disengagement by operation of said power means, and meansoperable to disengage said clutch to release said member from said powermeans to permit manual operation of said member.

2. In combination, a control device having a control member movable backand forth to a plurality of controlling positions, a motor mechanism foroperating said control member in either direction to move said member toany of its controlling positions comprising an oscillatable actuatingmember, a motor for driving said actuating member back and forth, meansincluding a releasable and resettable clutch device for normallyconnecting said control member to said actuating member for movementthereby, said clutch device permitting over-travel of said actu- 3. Incombination, a circuit breaker having relatively movable contacts and amechanism including an operating member movable back and forth to openand to closed position for opening and closing said contacts, powermeans operable to selectively move said member to open and to closedposition, means normally connecting said power means to said memberincluding a releasable and resettable clutch which is operable toautomatically release said member from the power means when the loadimposed on the operating member exceeds a predetermined safe value.

4. In combination, a circuit breaker having relatively movable contactsand an operating member movable back and forth for opening and closingsaid contacts, a motor mechanism for operating said member back andforth to open or to close said contacts, means releasably coupling saidmechanism to said member so as to permit overtrayel of said mechanismrelative to said member, said coupling means being operable toautomatically release said member from said mechanism whenever the loadimposed on said member exceeds a predetermined safe value, and

a manual operating member removably mountable on said coupling meansoperable to release said breaker operating member from said motormechanism to permit manual operation thereof.

5. In combination, a circuit breaker having relatively movable contactsand actuating means including an oscillatable operating member movableback and forth for opening and closing said contacts, a motor mechanismfor operating said member back and forth to effect opening or closing ofsaid contacts comprising a rocking lever, motor means for oscillatingsaid lever, means coupling said member to said lever for movementthereby, said coupling means yieldably permitting limited overtravei ofsaid lever relative to said member and being operable to automaticallyrelease said member from said lever whenever the load imposed on themember exceeds a predetermined valuei 6. In combination, a circuitinterrupter having relatively movable contacts and actuating meansincluding an oscillatable member movable back and forth for opening andclosing said contacts, a motor mechanism for operating said member backand forth to open or to close said contacts comprising a rotatablecrank, a motor for driving said crank, a rocking lever connected to saidcrank for oscillation thereby, an operating lever secured to saidoscillatable member, and releasable and resettable clutchmeans normallyconnecting said operating lever to said rocking lever for movementthereby, said clutch means being operable to automatically disconnectsaid operating lever from said rocking lever when the load imposedthereon by said rocking lever exceeds a predetermined maximum safevalue.

7. In combination, a circuit interrupter having relatively movablecontacts and actuating means including an oscillatable member movableback and forth for opening and closing said contacts, a motor mechanismfor operating said member back and forth to open or to close saidcontacts comprising a rotatable crank, a motor for driving said crank, arocking lever connected-to said crank for oscillation thereby, anoperating lever detachablysecured to said oscillatable member, and areleasable and resettable clutch means normally connecting saidoperating lever to said rocking lever for movement thereby, said clutchmeans permitting overtravel of said rocking lever relative to saidoperating lever.

8. In combination, a circuit interrupter having relatively movablecontacts and actuating means including an oscillatable member movableback and forth for opening and closing said contacts, a motor mechanismfor operating said member back and forth to open or to close saidcontacts comprising a rotatable crank, a motor for driving said crank, arocking lever connected to said crank for oscillation thereby, anoperating lever secured to said oscillatable member, and a releasableand resettable clutch means normally connecting said operating lever tosaid rocking lever for movement thereby, said clutch means yieldablypermitting limited overtravel of said rocking lever relative to saidoperating lever, and being operable to automatically release saidoperating lever from said rocking lever when the load imposed on saidoperating lever by said rocking lever exceeds a predetermined maximumsafe value, and said clutch means being resettable following release byoperation of said motor.

9. In combination, a circuit breaker having relatively movable contactsand means including an oscillatable operating member movable back andforth to open and to closed position for opening and closing saidcontacts, a motor mechanism operable to selectively move said member toopen or to closed position comprising an oscillatable actuating member,a motor for driving said actuating member, means including a releasableand resettable clutch device having a normal position in which itnormally connects said breaker operating member to said actuating memberin proper position relative to said actuating member for movementthereby, said clutch device permitting overtravel of said actuatingmember relative to said operating member and acting to assist instopping rotation of said motor when said actuating member reaches theend of its stroke, and said clutch device being operable toautomatically release said breaker operating member from said motordriven actuating member whenever the load on said breaker operatingmember exceeds a predetermined amount and being resettable to saidnormal position connecting said members, by the operation of said motormechanism.

10. In combination, a circuit interrupter having relatively movablecontacts and means including an oscillatable operating member movableback and forth for opening and closing said contacts, a motor mechanismfor operating said member back and forth to open or to close saidcontacts comprising an oscillatable actuating member, a motor fordriving said actuating member, a releasable and resettable clutch meansnormally connecting said operating member to said actuating member formovement thereby, said clutch means permitting overtravel of saidactuating member relative to said operating member and being operable toautomatically release said operating member'from said mechanism wheneverthe load imposed on saidoperating member exceeds a predetermined safevalue, and means operable to disengage said clutch to release saidoperating member from said mechanism to permit manual operation of theinterrupter.

11. In combination, a circuit interrupter having relatively movablecontacts and actuating means including an oscillatable operating membermovable back and forth for opening and closing said contacts, a motormechanism for operating said member back and forth to open or to closesaid contacts comprising an oscillatable aetuating member, a motor fordriving said actuating member, means releasably coupling said membersfor movement together, said coupling means permitting overtravel of saidactuating member relative to said operatingmember and being operable toautomatically release said operating member from the actuating memberwhenever the load imposed on said operating member exceeds apredetermined safe value, and means removably mounted on said operatingmember operable to release said operating member from said actuatingmember to permit manual operation of the interrupter.

12. In combination, a circuit interrupter having relatively movablecontacts and actuating means including an operating member movable backand forth to open and to closed position for opening and closing saidcontacts, a motor mechanism for selectively moving said member to openand to closed position comprising an oscillatable actuating member, amotor for driving said actuating member, releasable and resettablecoupling means for releasably coupling said operating member to saidactuating member for movement thereby, said coupling means permittingovertravel of said actuating member relative to said operating memberand being operable to automatically release said operating member fromthe actuating member whenever the load imposed thereon by said actuatingmember exceeds a predetermined safe value, said coupling meanscomprising a spring biased roller carried by 'one of said members forengaging a single roller receiving recess provided in the other of saidmembers.

13. In combination, a circuit interrupter having relatively movablecontacts and actuating means including an oscillatable operating membermovable back and forth to open and to closed position for opening andclosing said contacts, a motor mechanism for operating said member toopen and to closed position comprising an oscillatable actuating member,a motor for driving said actuating member, one of said members beingprovided with a single roller receiving recess and the other of saidmembers carrying a spring-biased roller for engaging said reces tonormally couple said operating member to said actuating member formovement thereby, the bias of said roller and the edges of said recessbeing such that said roller rides out of said recess to release saidoperating member from the actuating member whenever the load imposed onsaid operating member exceeds a predetermined safe value, and saidroller being resettable in said single recess following release, by theoperation of said motor.

14. In combination, a circuit interrupter having relatively movablecontacts and actuating means including an oscillatable operating membermovable back and forth for opening and closing said contacts, a motormechanism for operating said member back and forth to open or to closesaid contacts comprising an oscillatable actuating member, a motor fordriving said actuating member, one of said members being provided with aroller receiving recess and the other of said members carrying aspring-biased roller for engaging said recess to normally couple saidoperating member to said actuating member for movement thereby, the biasof said roller and the edges oisaid recessbeingsuchthatsaidroller ridesout of said recess to release said operating member from the actuatingmember whenever the load imposed on said operating member exceeds apredetermined safe value, and means operable to withdraw said rollerfrom said recess to release said operating member from the mechanism topermit manual operation of said operating member.

15. In combination, a circuit breaker having relatively movable contactsand actuating means including an operating member movable back and forthfor opening and closing said contacts and a trip device for eiifectingopening of said contacts independently of the pomtion 0! said member, amotor mechanism ior operating said member back and forth to open or toclose said contacts and to reset the breaker actuating means following atripping operation, said mechanism comprising an actuating member, amotor for driving said actuating member, means including a releasableand resettable clutch device for releasably connecting said operatingmember to said actuating member for movement thereby, said clutch devicepermitting over-travel oi said actuating member relative to saidoperating member and being operable to automatically release saidoperating member from the actuating member when the load imposed thereonexceeds a predetermined safe value.

16. In combination, a circuit breaker having relatively movable contactsand means including an oscillatable operating member for opening andclosing said contacts, a motor mechanism for operating said member backand forth comprising an operating lever detachably secured adjacent oneend to said operating member, a rocking lever pivoted on said operatinglever adjacent said one end, motor-driven means connected to saidrocking lever for rocking the same, means releasably coupling saidoperating lever to said rocking lever for movement thereby, saidreleasable coupling means permitting overtravel of said rocking leverrelative to said operating lever and being operable to automaticallyrelease said operating lever irom said rocking lever whenever the loadimposed on said operating member exceeds a predetermined safe value,said coupling means comprising a spring-biased roller carried by one ofsaid levers for engaging a roller receiving recess provided in the otherof said members.

17. In combination, a control device having an oscillatable controlmember movable to a pinrality of controlling positions, a motormechanism for selectively operating said member back and forth to any ofits controlling positions comprising an oscillatable actuatingmember, amotor for driving said actuating member, means including a releasableand resettable clutch device having a normal position in which itnormally connects said control member to said actuating member in properposition relative to said actuating member for movement thereby, saidclutch device permitting overtravel of said actuating member relative tosaid control member and being operable to assist in stopp fl rotation ofsaid motor when said actuating member reaches the ends of its stroke,and said clutch device being operable to release said control memberfrom said.

actuating member when the load on said control member exceeds apredetermined amoimt, said clutch being resettable to its normalposition connecting said members, by the operation of said motormechanism.

18. In combination, a control device having an oscillatabie controlmember movable to a plurality of controlling positions, a motormechanism for selectively operating said member to any of itscontrolling positions comprising an oscillatable actuating member, amotor for driving said actuating member, means including a releasableand resettable clutch device tor normally connecting said control memberto said actuating member for movement thereby, said clutch devicepermitting overtravel 01 said actuating member relative to said control--member and being operable to assist in stopping rotation of said motorwhen said actuating member reaches the ends of its stroke and toautomatically release said control member iro said actuating memberwhenever the load imposed on said control member exceeds a predeterminedsai'e value.

19. In combination, a control device having an oscillatable controlmember movable to a plurality of controlling positions, a motormechanism for selectively operating said member to any of itscontrolling positions comprising anoscillatable actuating member, amotor for driving said actuating member, means including a clutch devicefor normally connecting said control member to said actuating member formovement thereby, said clutch device permitting overtravel of saidactuating member relative to said control member and being operable toassist in stopping rotation of said motor when said actuating memberreaches the ends of its stroke and to automatically release said controlmember from said actuating member whenever the load imposed on saidcontrol member exceeds a predetermined safe value: and means operable todisengage said clutch to eiiect release oi said control member from saidmechanism to permit manual operation of said control member.

20. A releasable and resettable clutch device for normally connectingand osciliatable operating member of a circuit breakerto an oscillatableactuating member of a motor operating mechanism for operating thecircuit breaker, said clutch device comprising means carried by one ofsaid members forming a single arcuate roller receiving recess, and aspring biased roller carried by the other of said members and engaged insaid recess, said clutch device permitting limited overtravel of saidactuating member relative to said operating member and being operable toautomatically release said operating member from said motor operatingmechanism whenever the load imposed on said operating member exceeds apredetermined safe value, and meansmanuallyoperableto from said recessto permit manual operation oi said breaker operating member free of saidmotor operating mechanism.

21. A releasable and resettable clutch device for normally connecting anoscillatable operating memberoia circuitbreaker to an oscillatableactuatingmember oi amotoroperatingmechanism for operating the circuitbreaker, said clutch devicecomprisingmeanscarriedbyoneoisaid membersforming a single arcuate roller receiving,andaspringbiasedrollercarriedby the other otsaidmembersandinsaidrecess, said clutch device permitting limited overtravel oisaid actuating member relative to said operating member and beingoperable to automatically release said operating member from said motoroperating wherever the load imposed on said operating member apredeterresettable in said roller receiving recess after release of saidclutch, by operation of said motor mechanism.

22. In combination, a circuit breaker having relatively movable contactsand actuating means including an oscillatable operating member movableback and forth to open and to closed positions respectively for openingand closing said contacts, a motor operating mechanism operable toselectively move said breaker operating member to open or to closedposition comprising an oscillatable motor driven actuating membermovable back and forth to open and to closed position corresponding tothe open and closed positions of said breaker operating member, motormeans operable through a definite cycle for moving said actuating memberto open or to closed position and a releasable and resettable clutchdevice having a normal position in which it normally connects saidbreaker operating member to said motor driven actuating member in properrelation to said actuating member for movement thereby, said clutchdevice being automatically releasable to release said breaker operatingmember from said motor driven actuating member whenever the load on saidbreaker operating member exceeds a predetermined amount, and said clutchdevice being resettable to said normal position connecting said membersby the operation of said motor means.

23. In combination, a circuit breaker having relatively movable contactsand actuating means including an osciliatable operating member movableback and forth to open and to closed positions respectively, for openingand closing said contacts, a motor operating mechanism operable toselectively move said breaker operating member to open or to closedposition comprising an oscillatable motor driven actuating membermovable back and forth to open and to closed position corresponding tothe open and closed positions of said breaker operating member, motormeans operable through a definite cycle for moving said actuating memberto open or to closed position and a releasable and resettable clutchdevice comprising a spring biased roller carried by one of said membersfor engaging in a single roller receiving recess in the other of saidmembers to normally connect said breaker operating member to said motordriven actuating member in proper relation to said actuating member formovement thereby, said roller being automatically disengageable fromsaid recess to release said breaker operating member from said motordriven actuating member whenever the load on said breaker operatingmember exceeds a predetermined amount, and said roller being resettablein said single recess to reconnect said members, by the operation ofsaid motor means.

LEON R. LUDWIG. TURE LINDSTROM.

